elec and mech

[Parampreet Bhasin]

hey arjun

surely we can sit and decide on the basic structure if u want to. paras seems to be interested and would be a great help. we shud fix up a meeting wid PRK sir at the earliest. as for the idea given by akshat, i would say dat wud be easy to build and modify but it wont be ATV if u wanna cal it....the gear belt mechanism would make it too difficult to move it on a rough terrain and stering mechanism even tho very tough to implement shud be given a shot. also if budget is not a constraint and you have an estimate of the voltage and amperage of the batteries required i suppose there is ONE shop in lajpat rai which actually makes custom made batteries for weight,amps or volts specification if we need it.

chalo dats all for now.

tc

param

 

On 8/21/06, siddharth munjal <siddhart...@gmail.com> wrote:

see ...theyll be expensive...a 24v...i dunno abt the amperage...for approx 2000  2500 ..a.rnd that much i guess...and the amerage i guess will be sufficient...have to go to lajpat rai market to check:)
sid

---------- Forwarded message ----------
From: Arjun Sarwal < arjun...@gmail.com>
Date: Aug 21, 2006 12:06 AM
Subject: Re: mech stuff
To: IEEE-NSI...@googlegroups.com

Hi
Could you please give a rough estimate of the costs of the batteries(Li-ion) please

Thanks

On 8/20/06, siddharth munjal < siddhart...@gmail.com > wrote:

1)in my prev mail i said"poly carbonate"...lol..i meant polyprop obviously...i thik its a great material to work with
2)r u talkin abt the bike waalaa lead acid battreries...i dont think u wud need those...and they r heavy...and cumborsome...if we could bend the budget a bit... there r awesome batteries(expensiove ones) avaoible in lajpat rai...rechargable...Li ion i guess..which can be used...lighter ...much lighter..and take less space too..
3)the suspension is gonna be tricky...since the vehicle is all terrain.. it hink it shud be discussed wid PRK sir!

sid

On 8/20/06, Arjun Sarwal <arjun...@gmail.com > wrote:

First of all , anybody who contributes is a part of it. So as long as you contribute in whatever way that you can, you are a part of it.

Coming to the question of materials,
Going by the weight required to be carried on board and the fact that it is required for the vehicle to be rugged, metal is scoring more points in my opinion.

What we would require is more information of
a) Thickness/grade of metal required (refer specifications given below)
b) places selling the required metal
c) approximate costs of the same(required for submitting the proposal)

the following parts would comprise the bulk of the weight to be beared by the frame-->

-batteries (12V 7AH) -approx 4 but better to keep room for 6
-DC motors - two and appropriate belt-gear mechanism
-suspension system
-onboard motherboard and processor (hardly any weight)
-cameras,gps units and other electronics hardware modules (hardly any weight)



regards
 

Arjun

ps- if param you can spare abt 3-4 hrs on deciding the basic shape,structure of the robot that would be quite useful

On 8/20/06, Parampreet Bhasin <parampre...@gmail.com > wrote:

now dats de way i wud like ques to be put....straight to de pt

luk there are very few vendors havin polyproplene but they kno it's strength vs thickness ratio...tell them the area required and the weight and theyll tell u how much shud be the thickness..

considerin dat the frame wud be big and heavy i wud suggest u shud go for metallic materials. second hand iron sheets are common and not a bad alternative as they are as gud in strength as new ones..tell me if u want any other info....well am i still a part of it???

 

On 8/20/06, arjun sarwal < arjuns...@yahoo.com > wrote:

Thanks param for the useful info
Polypropylene thus seems like a good choice,
but a major point of concern is that for  larger values of weight, would we get suitably strong peices of polypropylene??
For example if there are about 4 lead acid batteries(12V,7AH) on the robot, and it is a huge frame, then would polypropylene be suitable?
also, please elaborate on metallic materials as possible options for the frame

Regards

Parampreet Bhasin < parampre...@gmail.com > wrote:

hey sid

i think wat u r sayin is pretty true...

i ll elaborate on the pros and cons of most materials i've used:

wood: cracks pretty often and de cracks keep widening....major prb is the screwin and unscrewin of nuts and bolts actually breaks all the internal tapping. even the cuttin  and stuff is tough

acrylic:

pros: plastic hence lightweight and excellent strength

cons:cant be joined wid regular adhesives but only wid chloroform etc. which used in excessive qty can actually reduce the strength of joint. so if u go ahead wid this do use mechanical joints like screws etc.

another prb is the cuttin ...its not dat easy

polyproplene:

well can be joined wid regular adhesives where moderate strength joints are needed....for other s i prefer mechanical joints. also the strength is pretty gud.

cons: price a lil higher and also not widely available.
i hope de above info was helpful...tc

param
 

On 8/19/06, siddharth munjal <siddhart...@gmail.com > wrote:

ok
all im saying is..

that wood is not a nice material to work with

see if u wont extreme workability....then polycarbonate(i think) will do...its a soft material...but has decent strength ...can carry quite a bit of wheight...spply thick sheets

strength...u can use that material...hmm....acrylic...verry brittle but yet very strong.....
or maybe that material u(arjun) used for tht internet controlled robo

see metal...some lightweight thing....with nice strength will be another nice option...but will be tuffff to work with..so NO-NO

there'll be millions of materials we can work with ...but we need to know the finer details of the robo before that

well if the kinda weight the robo has to carry is decided....then the material can be decided more effectively

and + im no1 to comment ...my experience is limited...we can ask parampreet for suggestions....and better still..consult PRK sir....i can talk to him if any of u want me to

siddharth

On 8/19/06, Arjun Sarwal <arjun...@gmail.com > wrote:

hi Siddharth
thanks for the useful information
but could you please elaborate a little on why you suggest so?
somthing from your experience tells you so probably..share your experience please

On 8/17/06, siddharth munjal <siddhart...@gmail.com > wrote:

are u guys gonna use wood for the cosntruction.i thnk ts a bad idea.u should use some kind of graphite materials or some kind of plastic....it should be light and give it the required strength.Wood is easy to work on .....but not a nice material to use.

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